Goldman Sachs chief Lloyd Blankfein has agreed to testify at the trail of Galleon Group founder Raj Rajaratnam, who’s been accused to trading on inside information including Goldman’s stock.

Blankfein is expected to testify to phone calls he made to Rajaratnam’s pal and former Goldman director, Rajat Gupta, who was charged this week with passing on confidential board secrets to Goldman and Procter & Gamble, where he also sat on the board.

Speculation about Blankfein’s appearance emerged yesterday afternoon after Rajaratnam’s attorney filed court papers saying the government’s witness list includes “numerous Goldman Sachs and Procter & Gamble representatives” who are expected to testify on behalf of the government’s case against Rajaratnam.

Blankfein has not been accused of any wrongdoing, but the Securities and Exchange Commission this week accused former Goldman director Gupta of taking information he learned from Blankfein and other board members to help Rajaratnam with his trading.

For example, in June, 2008, Blankfein allegedly called Gupta for eight minutes at 5:41 p.m. to discuss second-quarter earnings, which had been better than expected. According to the SEC complaint, Gupta called Rajaratnam a few hours later and Rajaratnam increased his stake in Goldman’s stock several times over the next several days, resulting in $13.6 million in ill-gotten gains for Galleon when earnings were finally revealed.

Spokespeople for Goldman and Manhattan US Attorney Preet Bharara’s office declined to comment on whether Blankfein would be testifying at the trial, which starts Tuesday.

The SEC charges against Gupta, former head of McKinsey & Co., also accuse him of leaking to Rajaratnam confidential information about Procter & Gamble.